Mishra, S., Bhatnagar, S., Goyal, G.N., Rana, S.P., & Upadhya, S.P. (2012). A comparative efficacy of amitriptyline, gabapentin, and pregabalin in neuropathic cancer pain: A prospective randomized double-blind placebo-controlled study. American Journal of Hospice and Palliative Care, 29, 177–182.

To compare the efficacy of amitryptylline, gabapentin, and pregabalin in patients with cancer experiencing neuropathic pain

Patients were randomly assigned to amitryptyllin (AT), gabapentin (GB), pregabalin (PG), or placebo. AT was given at 50 mg/day for one week, then increased incrementally to 100 mg/day. GB was given at 900 mg/day for one week in divided doses, then increased to 1,800 mg/day by week 3. PG was given at 150 mg/day for one week, then increased to 600 mg/day by week 3. The control group received placebo capsules. Morphine was used as rescue pain medication as needed. Patients were evaluated weekly for four weeks.

• The study reported on 120 patients.
• Information on patient age and key disease characteristics was not provided.

• Single site    
• Setting not specified
• India

The study has clinical applicability for late effects and survivorship.

The study was a placebo-controlled, randomized trial.

• Visual analog scale (VAS) to measure pain globally as well as burning, lancinating pain and dysesthesia
• Eastern Cooperative Oncology Group (ECOG) score for functional capacity
• Global satisfaction rating on a five-point verbal scale

VAS scores decreased in all groups. In week 4, those on pregabalin had significantly lower VAS scores than other groups, and scores declined by 4–5 points (p < 0.03). By the third visit, the percentage of patients who required morphine rescue increased: 46.7% with AT, 23.3% with GB, 16.7% with PG, and 100% with placebo. Lancinating pain incidence was lowest in the PG group. There were significantly fewer patients with dysesthesia in the PG group (6.7%) compared to the GB and placebo groups after four weeks. The percentage of patients with allodynia declined in all groups. The PG group showed a statistically significant improvement in ECOG score compared to all other groups (p < 0.001). Satisfaction was similar in all groups, and there were no significant differences in adverse reactions, with a gradual increase in all groups over time. Adverse effects were somnolence, dizziness, nausea, constipation, and dry mouth.

All of the drugs tested here demonstrated some efficacy in improving neuropathic symptoms. In several areas, it appears that pregabalin was more effective than gabapentin, opioid monotherapy, and amitryptylline. All medications were given in combination with opioids for pain management.

• No information of opioid dosages in each group was provided for comparison.
• The follow-up period of four weeks was relatively short, given the usual duration of symptoms.
• No information was provided regarding the causes of peripheral symptoms (whether they were chemotherapy-induced or related to other causes).

All of the medications examined in this study were effective and had a morphine-sparing effect in the treatment of neuropathic pain and other symptoms. Pregabalin was more effective than other alternatives tested in some areas. As all patients in this study received opioids for pain rescue, it should be noted that essentially all medications compared were given in combination with opioids.